The broad use of membrane filtration and electrochemical systems to detect microorganisms in various samples is well known. Membrane filtration normally requires a minimum of twenty-four hours incubation time for adequate growth to appear and requires the use of an operator to examine and count the microorganism colonies. Electrochemical detection systems presently employed have the inherent disadvantage of a high probability of missing cells when present in small numbers in large volumes and there is, at times, a long lag time to produce the required number of 10.sup.6 to 10.sup.7 cells/ml for a detectable response to occur in the system.
In the present invention an attempt is made to combine the advantageous features of both the membrane filtration and electrochemical detection systems while minimizing the disadvantages thereof.
It is therefore an object of the present invention to provide a novel apparatus and process for detecting and enumerating specific microorganisms in a sample solution.
It is another object of the present invention to combine the membrane filtration and electrochemical microbial detection systems into a simple system that may be readily employed by semiskilled operators to detect and enumerate microorganisms in a sample solution.
Another object of the present invention is a rapid process for determining water contamination of small numbers in large volumes.
Another object of the present invention is a novel apparatus for qualitatively and quantitatively detecting water sample impurities.
According to the present invention the foregoing and additional objects are attained by filtering a sample solution through a standard membrane filter impervious to the microorganism tested for, placing the membrane filter onto an absorbent pad previously moistened with a microorganism growth stimulant medium, positioning a pair of platinum electrodes on the filter surface and covering the electrodes with a second identically treated absorbent pad. This assembly is then sealed within a petri dish or like container with one exposed end of each electrode protruding from the sealed container being connected to a suitable recorder for detecting and recording the microbial growth.